The present invention relates to an improvement in the methods used to control the position of farm implements, such as harvesters, relative to the location of the individual plants of a row crop within which the implement is being employed. More specifically, to a method of automatically adjusting the relative position of such implements in regards to the row crop without requiring the operator to make constant adjustments to the attitude of the towing vehicle.
The production of row crops such as sugar beets requires the use of specialized farm implements such as cultivators and harvesters that are drawn through the field during cultivating and harvesting operations. These procedures require that the farm implements be properly oriented at all times relative to the individual plants and their related rows comprising the row crop. This requirement creates difficulties as it is very hard for the operator of the towing vehicle to maintain the proper orientation as he travels up and down the row crop both because the rows are never completely straight and the towing vehicle may tend to wander relative to a straight line due to surface conditions or problems in the directional control apparatus of the towing vehicle. The potential wandering of the tow vehicle is transferred to the towed implement leading to positional variances in the horizontal plane between the implement's diggers the plants constituting the row crop. These horizontal variances often lead to damage to the crop as the diggers can be far enough off line to result in a destroyed or entirely missed plants.
Additionally, variances in the level or composition of the field surface can create problems in the vertical orientation of the towed implement causing the attached diggers to dig too deeply or to skip over entire sections of the row crop. Again, this misalignment in the vertical orientation can result in damage to the crop and implement or to a situation where sections of the row crop are left uncultivated or unharvested in the field, either of which are undesirable to the farmer.
In the past many possible solutions to these problems have been proposed, some of which are illustrated in the prior art. The most relevant of these for the purposes of the present invention is illustrated in U.S. Pat. No. 4,031,962 issued to Ellinger which describes an apparatus to control both the vertical and horizontal orientation of a harvester to which it is attached. The provided apparatus operates by the use of a pair of elongated sensing shoes that are positioned below the harvester so that they run along the surface of the ground during field operations in a manner so that each of the individual sensing shoes pass on opposite side of the row crops measuring changes in both the vertical and horizontal orientation of the row crop and making the appropriate adjustments to the relative position of the towed implement.
While the described apparatus accomplished its stated goals, a problem with its design results in deficits in its sensitivity and responsiveness that limit its overall effectiveness in the function for which it was designed. This problem is a result of the manner employed to pivotally attach the sensing shoes to the remaining portion of the apparatus in that they are not freely pivotal in all axises and therefore limited in their range of motion. This method of construction results in an apparatus that is less sensitive and responsive than is desirable and therefore, of limited value to the row crop farmer.
Therefore, it can be seen that it would be desirable to provide a mechanism which monitors the vertical and horizontal position of a towed implement and its attached diggers relative to the individual plants and rows of a row crop such as sugar beets. Additionally, that this apparatus be sensitive enough to accurately guide the harvester or other like implement through the rows of a row crop to maximize its operational potential in field operations.